Nicene and Post-Nicene Fathers, Ser. II, Vol I:
The Life of Constantine with Orations of Constantine and Eusebius.: Chapter XXXIV

Chapter XXXIV.—That he wrote to Eusebius respecting Easter, and respecting Copies of the Holy Scriptures.

Ever careful for the welfare of the churches of God, the emperor addressed me personally in a letter on the means of providing copies of the inspired oracles, and also on the subject of the most holy feast of Easter. For I had myself dedicated to him an exposition of the mystical import of that feast; and the manner in which he honored me with a reply may be understood by any one who reads the following letter.